Hi I ordered a 50 watt kit from Valvestorm, Should ship tomorrow. I'm excited and can't wait for it to get here. Also new here to the forum and wanted to drop by and say Hi. This will be my second build (JTM45)
was my first. I've been lurking and reading a lot on this forum , And I like what I see and read so far. If I run into any questions I'll be on here posting... Otherwise it should go smooth.. Thanks,
harleytech

Ok Guy's , I got the kit all together all my voltages checked out, installed the tubes, powered up hooked up my 4x12 cab and plugged in my strat and played for a couple seconds and all of a sudden I get this what sounds like to me is a very loud piercing hum and I hit standby it goes away take it off standby start to play the guitar and that loud hum comes right back as soon as you start playing.. This happens in or out of the head case.. I checked all my wiring about 10 times, All where its supposed to be.. Checked all my grounds even added ground wires to my buss wire on the back of the pots.. made short leads to the important wires.
moved wires away from other wires. Anyone have any ideas what to check next.. Tubes are new Tung-Sol preamp and power tubes. Any help would be great , Or if anyone has had the same problem , Chime in..
The kit is a metro 50 watt built to lead specs per the instruction PDF. Thanks,
harleytech...

Another thought.. Would changing my Negative Feedback resistor help ? there is a 47k there now..
Or would moving the wire to the 16 0r 8ohm tap help.. The 4x12 cab I have is 16 0hm's..Just some ideas I have.. The red & white OT wires to the power tubes are hooked up right , I tried switching them and it made it worse.. I had the high pitch squeal right away when I did that, So I moved them back.. But the sound was the same as I am getting now. That's why I'm thinking is has to do with that feedback circuit.
Thanks,
harleytech..

Well all is fixed.. !!! I figured it out myself...
What it was, The three wires coming out of the OT (Red-blue-white) Classic Tone OT I had Put the red & white on V4 and V5 - like in the PDF installation Instructions (Different colors in the PDF) - Well I tried swapping the red and white and it was worse , So after thinking about it for a while I just said hey what if I leave the red where it's at on V4 and swap around the blue and white - That was the ticket.. Amp sounds great now ! I love it ! no more loud squealing noise.. Real quiet ... Until you start playing thru it.. Lol..
harleytech..

Haze13 wrote:This change in wires turns the negative feedback to positive feedback. It starts to oscillate... Every one who plays with tube amps (push-pull types) makes that mistake

That's what I'm hearing.. Oh well.. It sounds great now.. I just finished installing my PPIMV Master Volume.
I'm using the PEC pot and the added little mini turret and shielded cable all from Valvestorm.. Same place I got my Amp kit.. Sounds great at low volumes , Does not sound tinny or looses body. Still sounds full.. Well I'm one happy Camper now !
harleytech..